1. Field of the Invention
The present invention relates to a rotor assembly of a brushless direct. current motor, wherein the rotor can be conveniently assembled and fixed.
2. Description of the Related Prior Art
A conventional brushless direct current motor of axial winding radial air gap in accordance with the prior art shown in FIG. 6 comprises a metallic axle tube 91 combined on a housing 90. The metallic axle tube 91 has an outer diameter combined with a circuit board 92, a coil 93, and pole plates 94. The metallic axle tube 91 has an inner diameter for combination with an oil-impregnated bearing 95 or a positioning bushing and a ball bearing, and a rotor has a magnet ring 96 to induce with the coil 93 to rotate.
During assembly of the conventional brushless direct current motor, it takes a lot of time to assemble the metallic axle tube 91 with the circuit board 92, the coil 93, the pole plates 94, and the oil-impregnated bearing 95. In addition, it needs a proper tightness between the metallic axle tube 91 and the circuit board 92, the coil 93, the pole plates 94, and the oil-impregnated bearing 95, thereby causing inconvenience in fabrication and assembly.
The objective of the present invention is to provide a rotor assembly of a brushless direct current motor, wherein the rotor can be conveniently assembled so that the brushless direct current motor can be manufactured and assembled more easily.
The present invention essentially includes a body provided with a circuit board, a pole plate, a coil, and a shaft base. The shaft base is provided with a positioning hole having a threaded portion by which a fixing member can be combined with a rotor. The rotor is provided with a countersunk seat in which a bearing is placed. The bearing has an axial hole for allowing passage of the fixing member so as to fix it. The rotor takes the fixing member as a center so as to rotate by a permanent magnet inducing with the coil.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.